1. Technical Field
The invention relates to the field of ink jet printers generally and, more particularly, to a fastening and connecting arrangement of tubular piezoelectric driving elements in writing heads of printers.
2. Description of the Prior Art
Write heads are known in ink writing devices which are provided with several writing nozzles in the form of ink channels for writing fluids, which in turn are shaped by hollowing out the write head according to German Pat. No. 25 43 451, which corresponds to U.S. Pat. No. 4,158,847. Ink droplets are discharged through the action of the piezoelectric elements, which cylindrically surround the ink channels over a fraction of their length, and which undergo deformation at a suitable command. This kind of arrangement makes possible the manufacture of write heads by casting the driving elements while concomitantly shaping out the ink channels. However, the strict requirements imposed by the molding of the ink channels involve considerable manufacturing input. In order to minimize this, a method is known whereby several piezoelectric driving elements are grouped into a so-called piezo-tubular bundle in accordance with German Pat. No. 32 34 408. According to the familiar procedure, the piezo-tubular bundle is introduced into a frame, and contact springs are provided for the piezoelectric driving elements which, when capped by a casing roof, close the electrical circuit to the piezo-tubular bundle. While it is true that mounting the piezo-tubular bundle directly as a so-called preassembled one-piece component represents a simplification of the production process, the precise positioning and fastening of the piezoelectric driving elements remain difficult to control and require relatively high manual skill. Furthermore, a necessary precondition for reliable contact is a strict correspondence between the position of the contact spring and that of the piezoelectric driving elements.